U.S. patent number 11,320,185 [Application Number 16/631,332] was granted by the patent office on 2022-05-03 for defrosting control method for multi-split system.
This patent grant is currently assigned to QINGDAO HAIER AIR-CONDITIONING ELECTRONIC CO., LTD.. The grantee listed for this patent is QINGDAO HAIER AIR-CONDITIONING ELECTRONIC CO., LTD.. Invention is credited to Shaojiang Cheng, Bin Shi, Ruigang Zhang, Wanying Zhang, Baitian Zhuo.
United States Patent |
11,320,185 |
Zhuo , et al. |
May 3, 2022 |
Defrosting control method for multi-split system
Abstract
A defrosting control method for a multi-split system is
provided. A multi-split system comprises an outdoor unit and
multiple indoor units. An expansion valve is provided on a
connecting pipeline between each of the indoor units and the
outdoor unit. When the expansion valve of each activated indoor
unit is closed and the degree of opening of the expansion valve of
each off-state indoor unit is less than or equal to a maximum set
degree of opening, the system satisfies a defrosting requirement,
and as a result the method controls the expansion valve of each
activated indoor unit to remain closed, thereby resolving the issue
of a dramatic temperature drop in a room having an activated indoor
unit during defrosting and improving user satisfaction. The degree
of opening of the expansion valve of a off-state indoor unit is
Off_PLS, and is controlled such that Off_PLS=ALL_HP*Avg_PLS/Off_HP.
The invention satisfies a defrosting requirement and reduces the
degree of opening of the expansion valves as much as possible,
thereby preventing damage to a compressor without affecting
defrosting.
Inventors: |
Zhuo; Baitian (Qingdao,
CN), Shi; Bin (Qingdao, CN), Cheng;
Shaojiang (Qingdao, CN), Zhang; Ruigang (Qingdao,
CN), Zhang; Wanying (Qingdao, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
QINGDAO HAIER AIR-CONDITIONING ELECTRONIC CO., LTD. |
Qingdao |
N/A |
CN |
|
|
Assignee: |
QINGDAO HAIER AIR-CONDITIONING
ELECTRONIC CO., LTD. (Qingdao, CN)
|
Family
ID: |
1000006279726 |
Appl.
No.: |
16/631,332 |
Filed: |
June 21, 2018 |
PCT
Filed: |
June 21, 2018 |
PCT No.: |
PCT/CN2018/092161 |
371(c)(1),(2),(4) Date: |
January 15, 2020 |
PCT
Pub. No.: |
WO2019/015444 |
PCT
Pub. Date: |
January 24, 2019 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
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US 20200208890 A1 |
Jul 2, 2020 |
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Foreign Application Priority Data
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Jul 19, 2017 [CN] |
|
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201710588909.7 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24F
11/43 (20180101); F24F 11/42 (20180101); F24F
1/14 (20130101); F25B 47/02 (20130101); F24F
1/0007 (20130101) |
Current International
Class: |
F25B
47/02 (20060101); F24F 1/0007 (20190101); F24F
11/42 (20180101); F24F 1/14 (20110101); F24F
11/43 (20180101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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104061651 |
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Sep 2014 |
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CN |
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104266423 |
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Jan 2015 |
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CN |
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104596032 |
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May 2015 |
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CN |
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105674648 |
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Jun 2016 |
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CN |
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106091505 |
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Nov 2016 |
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CN |
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106322580 |
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Jan 2017 |
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CN |
|
2000179969 |
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Jun 2000 |
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JP |
|
Primary Examiner: Nieves; Nelson J
Attorney, Agent or Firm: Chen; Jiwen Jacobson Holman
PLLC
Claims
What we claimed is:
1. A defrosting control method for multi-split system in need of
defrosting, wherein the multi-split system includes an outdoor unit
and a plurality of indoor units, an expansion valve is disposed on
each of connecting pipes between one of the indoor units and the
outdoor unit, includes: step (1): determining whether or not a
defrosting requirement is satisfied under a condition that
expansion valves on working indoor units are closed and the opening
degree of each of expansion valves of off-state indoor
units.ltoreq.a maximum set opening degree offLimitMaxPLS; step (2):
performing step (2a) or step (2b) as follows: step (2a): if the
defrost requirement is satisfied, closing the expansion valves of
the working indoor units and adjusting the opening degree of each
of the expansion valves of the off-state indoor units to Off_PLS,
wherein Off_PLS=ALL_HP*Avg_PLS/Off_HP; in which: Off_HP denoting a
total capacity of the off-state indoor units; Off_PLS denoting an
opening degree of each of the expansion valves of the off-state
indoor units; offLimitMaxPLS denoting a maximum set opening degree
of each of the expansion valves on the off-state indoor units;
ALL_HP denoting a total capacity of the indoor units, and Avg_PLS
denoting a set average opening degree, which indicates that if the
opening degree of each of the expansion valves of the indoor units
is the set average opening degree the multi-split system satisfying
the defrosting requirement; step (2b): if the defrosting
requirement is not satisfied under a condition that each of the
expansion valves of the working indoor units are closed and the
opening degree of each of the expansion valves of the off-state
indoor units.ltoreq.the maximum set opening degree offLimitMaxPLS;
adjusting the opening degree of each of the expansion valves of the
off-state indoor units to the maximum set opening degree
offLimitMaxPLS; and adjusting the opening degree of each of the
expansion valves of the working indoor units to On_PLS; wherein
On_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS)/On_HP; in which On_HP
denoting the total capacity of the working indoor units and On_PLS
denoting the opening degree of each of the expansion valves of the
working indoor units.
2. A defrosting control method for multi-split system according to
claim 1, wherein determining whether or not satisfying the
defrosting requirement by determining if under a condition that the
expansion valves of the working indoor units are closed and the
opening degree of each of the expansion valves of the off-state
indoor units.ltoreq.the maximum set opening degree offLimitMaxPLS
by determining whether
(Off_HP*offLimitMaxPLS).gtoreq.ALL_HP*Avg_PLS.
3. A defrosting control method for multi-split system according to
claim 1, further comprising: separating the indoor units into
normal indoor units and VIP indoor units; and in step (2b), if the
defrosting requirement is not satisfied under a condition that each
of the expansion valves of the working indoor units are closed and
the opening degree of each of the expansion valves of the off-state
indoor units.ltoreq.the maximum set opening degree offLimitMaxPLS,
then further determining whether or not the defrosting requirement
is satisfied under a condition that the opening degree of each of
the expansion valves of the off-state indoor units is the maximum
set opening degree offLimitMaxPLS, the opening degree of each of
expansion valves of working normal indoor units.ltoreq.a maximum
set opening degree onLimitMaxPLS, and each of expansion valves of
working VIP indoor units are closed; step (2b1): if the defrosting
requirement is satisfied, adjusting the opening degree of each of
the expansion valves of the off-state indoor units to the maximum
set opening degree offLimitMaxPLS; adjusting the opening degree of
each of the expansion valves of the working normal indoor units to
a NormalOn_PLS; wherein
NormalOn_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS)/NormalOn_HP;
and closing each of the expansion valves of the working VIP indoor
units; in which, NormalOn_HP denoting a total capacity of the
working normal indoor units; NormalOn_PLS denoting the opening
degree of each of the expansion valves of the working normal indoor
units, and onLimitMaxPLS denoting a maximum set opening degree of
each of the expansion valves of the normal working indoor units;
step (2b2): if the defrosting requirement is not satisfied under
the condition that the opening degree of each of the expansion
valves of the off-state indoor units is the maximum set opening
degree offLimitMaxPLS, the opening degree of each of expansion
valves of the working normal indoor units.ltoreq.the maximum set
opening degree onLimitMaxPLS, and each of expansion valves of
working VIP indoor units are closed: adjusting the opening degree
of each of the expansion valves of the off-state indoor units to
the maximum set opening degree offLimitMaxPLS; adjusting the
opening degree of each of the expansion valves of the working
normal indoor units to the maximum set opening degree
onLimitMaxPLS; and adjusting the opening degree of each of the
expansion valves of the working VIP indoor units to VIP_PLS,
wherein
VIP_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS-NormalOn_HP*onLimit
MaxPLS)/VIP_HP; in which, VIP_HP denoting a total capacity of the
working VIP indoor units; VIP_PLS denoting an opening degree of
each of the expansion valves of the working VIP indoor units.
4. A defrosting control method for multi-split system according to
claim 3, wherein the step for determining whether or not the
defrosting requirement is satisfied under the condition that the
opening degree of each of the expansion valves of the off-state
indoor units is the maximum set opening degree offLimitMaxPLS, the
opening degree of each of expansion valves of the working normal
indoor units.ltoreq.a maximum set opening degree onLimitMaxPLS, and
each of expansion valves of working VIP indoor units are closed
includes: determining whether
(Off_HP*offLimitMaxPLS)+(NormalOn_HP*onLimitMaxPLS).gtoreq.ALL_HP*Avg_PLS-
.
5. A defrosting control method for multi-split system according to
claim 1, wherein the maximum set opening degree of each of the
expansion valves of the off-state indoor units
offLimitMaxPLS=K1*Avg_PLS, 2.ltoreq.K1.ltoreq.3.
6. A defrosting control method for multi-split system according to
claim 5, wherein K1=2.
7. A defrosting control method for multi-split system according to
claim 3, wherein the maximum set opening degree of each of the
expansion valves of the working normal indoor units
onLimitMaxPLS=K2*Avg_PLS, 1.ltoreq.K2<2.
8. A defrosting control method for multi-split system according to
claim 7, wherein K2=1.5.
Description
This is a U.S. national stage application of PCT Application No.
PCT/CN2018/092161 under 35 U.S.C. 371, filed Jun. 21, 2018 in
Chinese, claiming priority of Chinese Application No.
201710588909.7, filed Jul. 19, 2017, all of which are hereby
incorporated by reference.
TECHNICAL FIELD
The invention belongs to the technical field of air conditioning,
and in particular relates to a defrosting control method for
multi-split system.
BACKGROUND
A typical multi-split system includes an outdoor unit connected to
a plurality of indoor units working independently. Each of the
indoor units is provided with an expansive valve configured to
adjust the amount of refrigerant flowing into indoor exchanger, and
the indoor exchanger transfer heat with the outside.
As the multi-split system working in a heating mode, frost may form
on the surface of the outdoor unit if the outdoor temperature is
low, and further exacerbate heat loss. It is necessary to enter a
defrost mode to defrost the outdoor unit and then back to normal
heating operation. During the defrost mode, the multi-split system
is running at a cold mode in which all of the indoor units,
regardless of working or not, are operating to cool the environment
such as to maintain the opening degree of the expansion valves are
same. In this way, the indoor temperature of rooms where the indoor
units working are decreased rapidly, which will affect user
experience.
SUMMARY OF THE INVENTION
The present invention provides a defrosting control method for
multi-split system to solve the problem that during the defrost
mode the indoor temperature of rooms where the indoor units working
may be decreased rapidly, and also to improve user experience.
In order to solve the above technical problems, the present
invention is implemented by the following technical solutions:
A defrosting control method for multi-split system, wherein the
multi-split system includes an outdoor unit and a plurality of
indoor units, an expansion valve is disposed on each of connecting
pipes between one of the indoor units and the outdoor unit;
The control method includes:
Determining whether or not satisfying a defrost condition;
If satisfying the defrost condition, determining whether or not
satisfying a defrosting requirement under a condition that
expansion valves on working indoor units are closed and the opening
degree of each of expansion valves of off-state indoor
units.ltoreq.a maximum set opening degree offLimitMaxPLS;
If satisfying the defrost requirement, closing the expansion valves
of the working indoor units and adjusting the opening degree of
each of the expansion valves of the off-state indoor units to
Off_PLS, wherein Off_PLS=ALL_HP*Avg_PLS/Off_HP;
in which:
Off_HP denoting a total capacity of the off-state indoor units;
Off_PLS denoting an opening degree of each of the expansion valves
of the off-state indoor units;
offLimitMaxPLS denoting a maximum set opening degree of each of the
expansion valves on the off-state indoor units;
ALL_HP denoting a total capacity of the indoor units, and;
Avg_PLS denoting a set average opening degree, which indicates that
if the opening degree of each of the expansion valves of the indoor
units is the set average opening degree the multi-split system
satisfying the defrosting requirement.
Further, determining whether or not satisfying the defrosting
requirement by determining if
(Off_HP*offLimitMaxPLS).gtoreq.ALL_HP*Avg_PLS under a condition
that the expansion valves of the working indoor units are closed
and the opening degree of each of the expansion valves of the
off-state indoor units .ltoreq.the maximum set opening degree
offLimitMaxPLS.
Further, the control method further includes:
If the defrosting requirement is not satisfied under a condition
that each of the expansion valves of the working indoor units are
closed and the opening degree of each of the expansion valves of
the off-state indoor units .ltoreq.the maximum set opening degree
offLimitMaxPLS;
Adjusting the opening degree of each of the expansion valves of the
off-state indoor units to the maximum set opening degree
offLimitMaxPLS; and
Adjusting the opening degree of each of the expansion valves of the
working indoor units to On_PLS; wherein
On_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS)/On_HP;
in which,
On_HP denoting the total capacity of the working indoor units;
On_PLS denoting the opening degree of each of the expansion valves
of the working indoor units.
Further, the control method further includes: separating the indoor
units into normal indoor units and VIP indoor units;
If the defrosting requirement is not satisfied under a condition
that each of the expansion valves of the working indoor units are
closed and the opening degree of each of the expansion valves of
the off-state indoor units .ltoreq.the maximum set opening degree
offLimitMaxPLS;
determining whether or not the defrosting requirement is satisfied
under a condition that the opening degree of each of the expansion
valves of the off-state indoor units is the maximum set opening
degree offLimitMaxPLS, the opening degree of each of expansion
valves of working normal indoor units.ltoreq.a maximum set opening
degree onLimitMaxPLS, and each of expansion valves of working VIP
indoor units are closed;
if the defrosting requirement is satisfied, adjusting the opening
degree of each of the expansion valves of the off-state indoor
units to the maximum set opening degree offLimitMaxPLS;
adjusting the opening degree of each of the expansion valves of the
working normal indoor units to a NormalOn_PLS; wherein
NormalOn_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS)/NormalOn_HP;
and
closing each of the expansion valves of the working VIP indoor
units;
in which,
NormalOn_HP denoting a total capacity of the working normal indoor
units;
NormalOn_PLS denoting the opening degree of each of the expansion
valves of the working normal indoor units, and
onLimitMaxPLS denoting a maximum set opening degree of each of the
expansion valves of the normal working indoor units.
Further, the step for determining whether or not the defrosting
requirement is satisfied under the condition that the opening
degree of each of the expansion valves of the off-state indoor
units is the maximum set opening degree offLimitMaxPLS, the opening
degree of each of expansion valves of the working normal indoor
units.ltoreq.a maximum set opening degree onLimitMaxPLS, and each
of expansion valves of working VIP indoor units are closed
includes:
Determining if
(Off_HP*offLimitMaxPLS)+(NormalOn_HP*onLimitMaxPLS).ltoreq.ALL_HP*Avg_PLS-
.
Preferably, if the defrosting requirement is not satisfied under
the condition that the opening degree of each of the expansion
valves of the off-state indoor units is the maximum set opening
degree offLimitMaxPLS, the opening degree of each of expansion
valves of the working normal indoor units.ltoreq.the maximum set
opening degree onLimitMaxPLS, and each of expansion valves of
working VIP indoor units are closed;
Adjusting the opening degree of each of the expansion valves of the
off-state indoor units to the maximum set opening degree
offLimitMaxPLS;
Adjusting the opening degree of each of the expansion valves of the
working normal indoor units to the maximum set opening degree
onLimitMaxPLS;
adjusting the opening degree of each of the expansion valves of the
working VIP indoor units to VIP_PLS, wherein
VIP_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS-NormalOn_HP*onLimitMaxPLS)/-
VIP_HP;
in which,
VIP_HP denoting a total capacity of the working VIP indoor
units;
VIP_PLS denoting an opening degree of each of the expansion valves
of the working VIP indoor units.
Further, the maximum set opening degree of each of the expansion
valves of the off-state indoor units offLimitMaxPLS=K1*Avg_PLS,
2.ltoreq.K1.ltoreq.3.
Further, K1=2.
Further, the maximum set opening degree of each of the expansion
valves of the working normal indoor units onLimitMaxPLS=K2*Avg_PLS,
1.ltoreq.K2<2.
Further, K2=1.5.
Compared with the prior art, the advantages and positive effects of
the present invention are: with the defrosting control method for
multi-split system disclosed by the present embodiment, the problem
that the indoor temperature where the working indoor units are
drops significantly could be solved by closing those expansion
valves of the working indoor units as the defrosting requirement of
the system is satisfied under the condition that the opening
degrees of each of those expansion valves of the off-state indoor
units are less than or equal to the maximum set opening degree, so
as to improve user experience. The method also solve problems of
compressor damage and being worsening in defrosting effect by
adjusting the opening degree of those expansion valves of those
expansion valves of the off-state indoor units as
Off_PLS=ALL_HP*Avg_PLS/Off_HP and in the meanwhile the defrosting
requirement of the system is satisfied.
Other features and advantages of the present invention will become
apparent from the Detailed Description of the Drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing the structure of a multi-split
system;
FIG. 2 is a flow chart of a defrosting control method for
multi-split system according to one embodiment of the present
invention;
FIG. 3 is a flow chart of a defrosting control method for
multi-split system according to another embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be further described in detail below
with reference to the accompanying drawings and embodiments.
FIG. 1 shows the structure of a multi-split system, and the
multi-split system includes an outdoor unit and a plurality of
indoor units; wherein an expansion valve is mounted on each of the
connecting pipe between one of the indoor units and the outdoor
unit. The expansion valve is disposed on an indoor unit liquid pipe
in which liquid refrigerate flowing so as to adjust the amount of
refrigerant entering the indoor unit. The indoor unit liquid pipe
is communicated with an outdoor unit liquid pipe. As shown in FIG.
1, an expansion valve 1 is disposed on a liquid pipe of the indoor
unit 1, an expansion valve 2 is disposed on a liquid pipe of the
indoor unit 2, and an expansion valve 3 is disposed on a liquid
pipe of the indoor unit 3 . . . . , an expansion valve N is
disposed on a liquid pipe of the indoor unit N.
The steps of the opening degrees of all of the expansion valves on
indoor units are same. If the expansion valve is in a closed state,
the opening degree is 0 step; if the expansion valve are in a full
opening state, the opening degree is 500 step. However, the
diameters of the expansion valves are different, the larger the
capacity of the indoor units, the larger of the diameter of the
expansion valve on the indoor unit.
A defrosting control method for multi-split system according to one
embodiment of the preset invention is shown in FIG. 2. The
defrosting control method mainly comprises following steps:
Step S11: determining whether or not satisfying a defrost
condition.
A temperature sensor is arranged on a heat exchanger of the outdoor
unit, which is configured to obtain the temperature of the outdoor
unit heat exchanger. If a detected temperature.ltoreq.a set
temperature, it is determined that a defrost condition is satisfied
and then starting a defrost mode; otherwise it is determined that
the defrost condition is not satisfied and maintaining a normal
operation.
If the defrosting condition is satisfied, a four-way valve switches
to a different position so as to enable the heating mode to be
changed to the cooling mode and all of indoor fans are turned off,
and performing Step 12.
Step S12: determining whether or not satisfying a defrosting
requirement under the condition that all of the expansion valves on
working indoor units are closed and the opening degree of each of
the expansion valves on off-state indoor units.ltoreq.a maximum set
opening degree offLimitMaxPLS.
If the defrosting requirement is satisfied, that is to say
achieving a required defrosting effect, performing Step S13
In the present embodiment, whether or not satisfying the defrosting
requirement is determined by if
(Off_HP*offLimitMaxPLS).gtoreq.ALL_HP*Avg_PLS. In fact, the indoor
unit capacities are different, with the same opening degree of the
expansion valves, the flow rates of refrigerant are varied, so the
defrosting effects are different. Hence, as determining whether or
not satisfying the defrosting requirement, the capacities of the
indoor units are preferably considered so as to evaluate the
defrost effect in a more reasonable way.
In which, Off_HP denotes a total capacity of all off-state indoor
units, that is to say a sum of the capacities of all of the
off-state indoor units, and offLimitMaxPLS denotes the maximum set
opening degree of each of those expansion valves of the off-state
indoor units.
ALL_HP denotes a total capacity of all indoor units, that is to say
a sum of the capacities of all of the indoor units. Avg_PLS denotes
a set average opening degree. If the opening degree of each of the
expansion valves of all indoor units is the set average opening
degree, the multi-split system satisfies the defrosting
requirement. The Avg_PLS is obtained from preset experiments during
which all of the opening degrees of the expansion valves of all
indoor units (including those working or at off states) are set to
an uniform opening degree so as to detect whether or not the
defrost of the outdoor unit heat exchanger could be completed
during a preset period; if the defrost of the outdoor unit heat
exchanger could be completed, it suggests that, with the current
uniform opening degree, the defrosting requirement of the
multi-split system could be satisfied to fulfill a required
defrosting effect, and then the current uniform opening degree is
set as the set average opening degree. For example, during a preset
experiment, all of the opening degrees of the expansion valves of
all indoor units are set as 150 steps, if the defrost of the
outdoor unit heat exchanger could completed during the preset
period, such as 5 minutes, the set average opening degree is set as
150 steps.
Step S13: closing the expansion valves of all working indoor units
and adjusting the opening degree of each of the expansion valves of
off-state indoor units to Off_PLS=ALL_HP*Avg_PLS/Off_HP.
The amount of refrigerant flowing into indoor unit heat exchanger
is being adjusted by the expansion valve. On one hand, if too much
refrigerant flowing into the indoor unit heat exchanger, the heat
exchange between the refrigerant and the indoor environment may be
insufficient such that the heat of the room where the indoor unit
disposed in could not be properly transfer to the refrigerant and
then used to defrost the ice of the outdoor unit for achieving a
required defrosting effect. If the ice could not completely melt,
the outdoor unit may frost again soon after back to normal heating
operation and leading to a gradual worsening heating performance.
In order to avoid that situation, as satisfying the defrosting
requirement, the opening degree of expansion valves of indoor units
are preferably set as small as possible meanwhile because the
smaller the opening degree of the expansion valve, the smaller heat
could be transferred to the refrigerant such that the indoor
temperature could be maintained without severe variation. On the
other hand, if each of those expansion valves of off-state indoor
units are fully opened, that is to say adjusting the opening degree
to a fully open degree, without consideration of different
capacities of the indoor unit heat exchangers and the defrosting
requirement of the outdoor unit, the refrigerant may be unable to
fully absorb the heat from the environment where the indoor unit
are such that a large part of liquid refrigerant not evaporating
may directly flow into compressor causing damage. In order to avoid
those problems, it is better to calculate an opening degree Off_PLS
for those expansion valves of off-state indoor units instead of
adjusting the opening degree in direct to the maximum set opening
degree offLimitMaxPLS even the defrosting requirement could be
satisfied under the condition that all of the expansion valves of
the working indoor units are closed and all of the expansion valves
of the off-state indoor units are set as the maximum set opening
degree offLimitMaxPLS. In this way, while satisfying the defrosting
requirement, the opening degree of the expansion valves of those
off-state indoor units could be maintained comparatively smaller so
as to avoid the worsening defrost effect caused by insufficient
heat exchange. Off_PLS denotes the opening degree of the expansion
valve of the off-state indoor unit.
Generally, if (Off_HP*offLimitMaxPLS).gtoreq.ALL_HP*Avg_PLS, those
expansion valves of the working indoor units are closed and the
opening degree of each of those expansion valves of the off-state
indoor units are set as Off_PLS; wherein
Off_PLS=ALL_HP*Avg_PLS/Off_HP, wherein
Off_PLS.ltoreq.offLimitMaxPLS.
With the defrosting control method for multi-split system disclosed
by the present embodiment, the problem that the indoor temperature
where the working indoor units are drops significantly could be
solved by closing those expansion valves of the working indoor
units as the defrosting requirement of the system is satisfied
under the condition that the opening degrees of each of those
expansion valves of the off-state indoor units are less than or
equal to the maximum set opening degree, so as to improve user
experience. The method also solve problems of compressor damage and
being worsening in defrosting effect by adjusting the opening
degree of those expansion valves of those expansion valves of the
off-state indoor units as Off_PLS=ALL_HP*Avg_PLS/Off_HP and in the
meanwhile the defrosting requirement of the system is
satisfied.
The defrosting control method for multi-split system disclosed by
the present embodiment could dynamically calculate the opening
degree of the expansion valve of each of the indoor unit according
to its real-time on-off states, and hence on one hand the impact on
the indoor temperature caused by defrosting could be minimized, on
the other hand the defrost requirement of the outdoor unit could be
satisfied.
In this embodiment, if the defrosting requirement is not satisfied,
that is to say (Off_HP*offLimitMaxPLS)<ALL_HP*Avg_PLS under the
condition that each of those expansion valves of the working indoor
units are closed and the opening degree of each of those expansion
valves of the off-state indoor units are less than or equal to the
maximum opening degree offLimitMaxPLS, performing Step 14.
Step S14: adjusting the opening degree of those expansion valves of
the off-state indoor units to the maximum set opening degree
offLimitMaxPLS; and adjusting the opening degree of those expansion
valves of the working indoor units as
On_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS)/On_HP, wherein On_HP
denotes the total capacity of all of the working indoor units and
On_PLS denotes the opening degree of those expansion valves of the
working indoor units.
If the defrost requirement could not be satisfied by merely
adjusting the opening degree of those expansion valves of the
off-state indoor units to the maximum set opening degree
offLimitMaxPLS, those expansion valves of the working indoor units
should be opened as well. Taking the worsening effect of the indoor
temperature into consideration, it is preferable to fully make use
of the adjustment effect of those off-state indoor units. Hence,
adjusting the opening degree of each of those expansion valves of
the off-state indoor units to the maximum set opening degree
offLimitMaxPLS and adjusting the opening degree of each of those
expansion valves of working indoor units to an average opening
degree, that is to say adjusting the opening degree of each of
those expansion valves of the working indoor units as On_PLS,
On_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS)/On_HP; and hence the
defrosting requirement is satisfied and the influence on the room
temperature where working indoor units in could be minimized.
As a preferred embodiment, the indoor units could be separated into
normal indoor units and VIP indoor units. During the defrosting
mode, the priority is to maintain the temperature of the rooms
where the VIP indoor units are not being influenced.
If the defrosting requirement is not satisfied, that is to say
(Off_HP*offLimitMaxPLS)<ALL_HP*Avg_PLS under the condition that
each of those expansion valves of working indoor units are closed
and the opening degree of each of those expansion valves of the
off-state indoor units.ltoreq.the maximum setting opening
offLimitMaxPLS, performing Step S15, as shown in FIG. 3.
Step S15: determining whether or not the defrosting requirement is
satisfied as the opening degree of each of those expansion valves
of the off-state indoor units is the maximum set opening degree
offLimitMaxPLS, the opening degree of each of those expansion
valves of the working normal indoor units.ltoreq.a maximum set
opening degree onLimitMaxPLS, and each of those expansion valves of
the working VIP indoor units are closed.
In this embodiment,
if
(Off_HP*offLimitMaxPLS)+(NormalOn_HP*onLimitMaxPLS).gtoreq.ALL_HP*Avg_-
PLS
the defrosting requirement is satisfied. The capacities of indoor
units are different, and the amount of refrigerant are varied under
a uniform expansion valve opening degree. Hence, this method
provides a reasonable way by considering into the capacities of the
indoor units.
If
(Off_HP*offLimitMaxPLS)+(NormalOn_HP*onLimitMaxPLS).gtoreq.ALL_HP*Avg_-
PLS,
the defrosting requirement could be satisfied without opening the
expansion valves of the working VIP indoor units, then performing
S16.
If
(Off_HP*offLimitMaxPLS)+(NormalOn_HP*onLimitMaxPLS)<ALL_HP*Avg_PLS,
the defrosting requirement merely could be satisfied by opening the
expansion valves of the working VIP indoor units, then performing
S17.
Step S16: adjusting the opening degree of each of those expansion
valves of the off-state indoor units to the maximum set opening
degree offLimitMaxPLS; adjusting the opening degree of each of
those expansion valves of the working normal indoor units to a
NormalOn_PLS; wherein
NormalOn_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS)/NormalOn_HP;
and closing each of those expansion valves of the working VIP
indoor units.
Wherein NormalOn_HP denotes a total capacity of all of the working
normal indoor units; NormalOn_PLS denotes the opening degree of
each of those expansion valves of working normal indoor units, and
onLimitMaxPLS denotes a maximum set opening degree of each of those
expansion valves of normal working indoor units.
If the defrosting requirement could be satisfied by adjusting the
opening degree of each of those expansion valves of all off-state
indoor units to the maximum set opening degree offLimitMaxPLS and
adjusting the opening degree of each of those expansion valves of
working normal indoor unit.ltoreq.the maximum set opening
onLimitMaxPLS, the influence on the temperature of the rooms where
the working normal indoor units in could be reduced by decreasing
the opening degree of those expansion valves of working normal
indoor units, that is to say, to adjust the opening degree of each
of those expansion valves of the working normal indoor units to
NormalOn_PLS, wherein
NormalOn_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS)/NormalOn_HP. In
this way, the defrosting requirement could be satisfied, and in the
meanwhile, the influence on the temperature of the rooms where
working normal indoor units in could be minimized and no impact on
the temperature of those rooms where VIP indoor units are.
Step S17: adjusting the opening degree of each of those expansion
valves of the off-state indoor units to the maximum set opening
degree offLimitMaxPLS; adjusting the opening degree of each of
those expansion valves of the working normal indoor units to the
maximum set opening degree onLimitMaxPLS;
adjusting the opening degree of each of those expansion valves of
the working VIP indoor units to VIP_PLS,
VIP_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS-NormalOn_HP*onLimitMaxPLS)/-
VIP_HP.
Wherein, VIP_HP denotes a total capacity of all working VIP indoor
units; VIP_PLS denotes an opening degree of each of those expansion
valves of working VIP indoor units.
After adjusting each of those expansion valves of all of off-state
indoor units to the maximum set opening offLimitMaxPLS and
adjusting each of those expansion valves of all of working normal
indoor units to the maximum set opening onLimitMaxPLS, the
defrosting requirement still may not be satisfied. Under this
condition, although the expansion valves of those working VIP
indoor units should be opened, the opening degree have to be
minimized so as to restrict the impact on the temperature of the
rooms where the working VIP indoor units are. It is preferable to
adjust the opening degree of each of those expansion valves of
working VIP indoor units to VIP_PLS, wherein
VIP_PLS=(ALL_HP*Avg_PLS-Off_HP*offLimitMaxPLS-NormalOn_HP*onLimitMaxPLS)/-
VIP_HP; and in this way, the defrosting requirement could be
satisfied and the influence on the temperature of the room where
the working VIP indoor units are could be minimized.
In the present embodiment, the maximum set opening degree of each
of those expansion valves of the off-state indoor units
offLimitMaxPLS is less than the opening degree when the expansion
valve is fully opened, offLimitMaxPLS=K1*Avg_PLS,
2.ltoreq.K1.ltoreq.3. The maximum set opening degree of each of
those expansion valves of the off-state indoor units within the
range could fully utilize the heat exchange capacities of off-state
indoor units to defrost, and meanwhile avoid the risk of compressor
damage caused by adjusting the opening degree to excess. As a
preferred embodiment, K1=2, and offLimitMaxPLS=2*Avg_PLS, which not
only could fully utilize the off-state indoor unit for defrosting,
but also ensures the defrosting effect, and avoids the risk of
compressor damage due to liquid refrigerant flowing into.
In the present embodiment, the maximum set opening degree of each
of those expansion valves of the working normal indoor units
onLimitMaxPLS is less than the opening degree when the expansion
valve is fully opened, onLimitMaxPLS=K2*Avg_PLS,
1.ltoreq.K2.ltoreq.2. The maximum set opening degree of each of
those expansion valves of the working normal indoor units within
the range could not only utilize the heat exchange capacities of
working normal indoor units to defrost, but also could avoid the
drop of temperature of the rooms where working normal indoor units
are. As a preferred embodiment, K2=1.5, and
onLimitMaxPLS=1.5*Avg_PLS, which not only could utilize the working
normal indoor units for defrosting, but also ensures the defrosting
effect, and avoids the drop of temperature of the rooms where
working normal indoor units are.
For example, when the expansion valve is fully opened, the opening
degree is 500 steps, the Avg_PLS is 150 steps, the offLimitMaxPLS
is 300 steps, and the onLimitMaxPLS is 225 steps.
The aim of the defrosting control method of the embodiment gives
priority to the comfort of the user in rooms where VIP indoor units
are, and secondly to the comfort of the user in rooms where normal
indoor units are, thereby ensuring the defrost effect and
minimizing the impact on temperature of rooms where working indoor
units are during the defrosting process, so as to improve user
satisfaction.
A formula for calculating an opening degree of each of expansion
valves of indoor units during defrosting process is provided:
(VIP_HP*VIP_PLS)+(NormalOn_HP*NormalOn_PLS)+(Off_HP*Off_PLS)=ALL_HP*Avg_P-
LS.
Under normal circumstances, VIP_PLS could be set to 0. That is to
say, only under the condition that the defrosting requirement still
could not be satisfied with both of the opening degree of each of
those expansion valves of working normal indoor units and the
opening degree of each of those expansion valves of off-state
indoor units are the maximum set opening degree, the expansion
valves of the working VIP indoor units are opened to ensure
defrosting effect.
Taking eight indoor units as an example, the defrosting control
method includes the following steps:
TABLE-US-00001 TABLE 1 Indoor Unit Number 1# 2# 3# 4# 5# 6# 7# 8#
Capacity HP 2 1 3 2.5 2 1.5 3 5 VIP Mark NO YES NO NO NO NO YES
NO
The total capacity of all indoor units is
ALL_HP=2+1+3+2.5+2+1.5+3+5=20.
Setting Avg_PLS=150, onLimitMaxPLS=225 and offLimitMaxPLS=300.
ALL_HP*Avg_PLS=20*150.
Condition 1:
TABLE-US-00002 Indoor Unit Number 1# 2# 3# 4# 5# 6# 7# 8# On-Off
Mark ON OFF OFF OFF ON ON ON OFF Opening Degree of Expansion Valve
0 261 261 261 0 0 0 261
The total capacity of all off-state indoor units is
Off_HP=1+3+2.5+5=11.5, which is the sum of the capacities of 2 #, 3
#, 4 #, 8 # indoor units.
The total capacity of all working normal indoor units is
NormalOn_HP=2+2+1.5=5.5, which is the sum of capacities of 1 #, 5
#, 6 # indoor units.
The total capacity of all working VIP indoor units is VIP_HP=3,
which is the capacity of 7 # indoor unit because 3 # indoor unit is
not working.
Since 11.5*300>20*150, the defrost requirement can be satisfied
by merely opening the expansion valves of those off-state indoor
units, VIP_PLS=0, NormalOn_PLS=0,
Off_PLS=(20*150)/11.5=261<300.
That is to say, when VIP_PLS=0 and NormalOn_PLS=0,
Off_PLS=(20*150)/11.5=261<300, the defrosting requirement is
satisfied and also the heating performance of the working VIP
indoor units and the working normal indoor units could be ensured
to avoid the drop of room temperature.
Condition 2
TABLE-US-00003 Indoor Unit Number 1# 2# 3# 4# 5# 6# 7# 8# On-Off
Mark ON OFF ON OFF ON ON ON OFF Opening Degree of Expansion Valve
53 300 53 300 53 300 0 300
The total capacity of all of the off-state indoor units is
Off_HP=1+2.5+5=8.5, which is the sum of the capacities of 2 #, 4 #,
and 8 # indoor units.
The total capacity of all working normal indoor units is
NormalOn_HP=2+3+2+1.5=8.5, which is the sum of the capacities of 1
#, 3 #, 5 #, and 6 # indoor units.
The total capacity of all working VIP indoor units is VIP_HP=3,
which is the capacity of 7 # indoor unit.
Since 8.5*300<20*150, 8.5*300+8.5*225>20*150, the defrosting
requirement can be satisfied by opening the expansion valves of
those off-state indoor units and the expansion valves of those
working normal indoor units, VIP_PLS=0, Off_PLS=300,
NormalOn_PLS=((20*150)-(8.5*300))/8.5=53<225.
That is to say, when VIP_PLS=0 and NormalOn_PLS=0,
Off_PLS=(20*150)/8.5=353>300, which is beyond the maximum set
opening degree and unable to satisfy the defrosting requirement of
the multi-split system. The expansion valves of those working
normal indoor units need to be opened and the method gives priority
to maintain the temperature of rooms where the working VIP indoor
units are. Then it could be obtained that
NormalOn_PLS=((20*150)-(8.5*300))/8.5=53<225 as VIP_PLS=0 and
Off_PLS=300.
Condition 3: 1 # and 5 # are added as VIP indoor units.
TABLE-US-00004 Indoor Unit Number 1# 2# 3# 4# 5# 6# 7# 8# Capacity
HP 2 1 3 2.5 2 1.5 3 5 VIP Mark YES YES NO NO YES NO YES NO On-Off
Mark ON ON ON ON ON ON ON ON Opening Degree of Expansion 38 38 225
225 38 225 38 225 Valve
The total capacity of all off-state indoor units is Off_HP=0.
The total capacity of all working general indoor units is
NormalOn_HP=3+2.5+1.5+5=12, which is the sum of the capacities of 3
#, 4 #, 6 #, 8 # indoor units.
The total capacity of all working VIP indoor units is
VIP_HP=2+1+2+3=8, which is the sum of the number of the capacities
of 1 #, 2 #, 5 #, and 7 # indoor units.
Since 12*225<20*150, the defrost requirement only could be
satisfied by opening both of the working normal indoor units and
the working VIP indoor units, NormalOn_PLS=225,
VIP_PLS=((20*150)-(12*225))/8=38.
That is to say, when VIP_PLS=0, Off_PLS=300,
NormalOn_PLS=(20*150)/12=250>225, which is beyond the maximum
set opening degree and unable to satisfy the defrosting requirement
of the multi-split system or the drop of temperature of rooms where
working normal indoor units are is significant. The expansion
valves of those working VIP indoor units need to be opened to
balance the system. Then it could be obtained
VIP_PLS=((20*150)-(12*225))/8=38, as Off_PLS=300 and
NormalOn_PLS=225
This written description uses examples to disclose the invention,
including the best mode, and also to enable any person skilled in
the art to practice the invention, including making and using any
devices or systems and performing any incorporated methods. The
patentable scope of the invention is defined by the claims, and may
include other examples that occur to those skilled in the art. Such
other examples are intended to be within the scope of the claims if
they have structural elements that do not differ from the literal
language of the claims, or if they include equivalent structural
elements with insubstantial differences from the literal language
of the claims.
* * * * *